Natural language is highly complex and can be challenging for some learners, yet the contribution of complexity to individual differences in language learning remains poorly understood. This poor understanding appears due to both a lack of consensus among researchers regarding what complexity is, and to on-line language research often employing…

We report on a study of first-exposure learners with different first languages (L1s: English, Japanese) to examine their ability to process input for form and meaning. We used a rich set of tasks to tap respectively into processing, comprehension, imitation, and working memory. We show that there are advantages to having a first language (L1) that…